Synopsis

Description

CREATE COLLATION defines a new
collation using the specified operating system locale settings, or
by copying an existing collation.

To be able to create a collation, you must have CREATE privilege on the destination schema.

Parameters

name

The name of the collation. The collation name can be
schema-qualified. If it is not, the collation is defined in the
current schema. The collation name must be unique within that
schema. (The system catalogs can contain collations with the same
name for other encodings, but these are ignored if the database
encoding does not match.)

locale

This is a shortcut for setting LC_COLLATE and LC_CTYPE at
once. If you specify this, you cannot specify either of those
parameters.

lc_collate

Use the specified operating system locale for the LC_COLLATE locale category. The locale must be
applicable to the current database encoding. (See CREATE DATABASE for the precise
rules.)

lc_ctype

Use the specified operating system locale for the LC_CTYPE locale category. The locale must be
applicable to the current database encoding. (See CREATE DATABASE for the precise
rules.)

existing_collation

The name of an existing collation to copy. The new collation
will have the same properties as the existing one, but it will be
an independent object.

Notes

Use DROP COLLATION to remove
user-defined collations.

See Section 22.2 for more
information about collation support in PostgreSQL.

Examples

To create a collation from the operating system locale
fr_FR.utf8 (assuming the current database
encoding is UTF8):

CREATE COLLATION french (LOCALE = 'fr_FR.utf8');

To create a collation from an existing collation:

CREATE COLLATION german FROM "de_DE";

This can be convenient to be able to use
operating-system-independent collation names in applications.

Compatibility

There is a CREATE COLLATION statement
in the SQL standard, but it is limited to copying an existing
collation. The syntax to create a new collation is a PostgreSQL extension.